The major goal of this project is to determine whether exercise training and dietary restriction can reduce the suppressive effects of free fatty acids (FFA) on insulin-mediated glucose disposal in a group of moderately obese older men and women with impaired glucose tolerance. Subjects will perform either 12 weeks of exercise training while consuming a eucaloric diet or 12 weeks of similar exercise training while consuming a hypocaloric diet designed to reduce body weight by 10-15%. To assess whether the metabolic adaptations to exercise and weight loss are related to varying body fat distribution, half of the subjects will have predominantly upper body obesity while half will have predominantly lower body obesity. Adaptations to the exercise and dietary interventions will be determined during euglycemic hyperinsulinemic clamps with normal and elevated FFA levels.